You don't get any more interests if you have more than 2000 MilBucks in the bank. (you have enough MilBucks already Acerbus... )
But you can still deposit as much MB as you like.

This is not because I don't want you to get more MilBucks, but because if you have more than 2000MB you have more than enough for most of the forum features anyway, and there would just become too much money in the bank..